Using numerical simulations we study the formation of thick films. We expect that the gross features of their morphology result from the combination of a few number of general processes. For instance, this could be the case of passive films formed on a lithium surface. Starting from this example a model of growth on a two dimensional lattice is proposed. It is based on the existence of chemical reactions which occur in the presence of a poison. It differs from the popular Eden model by the fact that the evolution probability of one site on the lattice depends on the local structure of the layer in formation. The numerical simulations show that different morphologies may appear for the bulk part of the layer. We hope that this model might be useful to describe a large class of growth processes in which the formation of a thick film is initiated by chemical reactions.